Best way to adjust cutter position in a running program?

[durl jones]

I am new to Mach3 and writing Gcode - but like it so far.

My question:
I am milling repeat pieces that have the same x and y profile but have variation in the z height.  I have set up a part fixture to hold my blanks and written the program to home up first and then go to my blank to begin machining.  I am in the absolute coordinate system.  I would like to be able to set my Z position higher than the highest blank I will be using and then lower it to the correct height once I begin machining.  When I pause the program and lower the Z it goes back to the original height.

I'm sure I am missing some basic concept for adjusting the cutter position while in an executing program?

Thanks,
Durl

[alenz]

Durl
Try changing offsets. Add a G55 (Offset #2) just ahead of the pause (M00 ?) line. Then reset the Z-DRO. The file will now run at the new Z-offset. At the appropriate place near the file end enter a G54 to return to offset #1 and return to your original Z for the next run.
Note, this will offset the entire file in the Z, i.e., outline cuts will cut deeper into your spoilboard, etc. Not sure if that is what you were asking.
HTH
 Al

[angel tech]

have seperate programs for each job

[durl jones]

Thanks for the suggestions!